A massive blast has killed at least five people in the southern Russian city of Vladikavkaz where a car exploded in a crowded market.

At least another 20 people were wounded in the explosion which caused panic at the market.

With fears of a second blast, those uninjured ran for their lives.

Police immediately ringed the market and set up road blocks.

Officials have said they are not sure what caused the explosion which also shattered windows in nearby buildings.

Vladikavkaz is the capital of the Russian republic of North Ossetia, which lies in Russia’s North Caucasus region.

The city has seen some racial unrest in recent months with ethnic tensions coming to the fore.

In November 2008, the mayor of the city was killed when an assassin shot him near his home.

It was also the scene of the 2004 Beslan crisis, in which Chechen separatist fighters killed 330 people; half of them children.